<!DOCTYPE html>
<meta charset="utf-8">
<title>CSS Reference</title>
<style>
#scrollContainer {
  overflow: scroll;
  font: 16px / 32px serif;
  height: 4lh;
  border: 1px solid black;
}
.clamp {
  display: flow-root;
  padding: 0 4px;
  white-space: pre;
  background-color: yellow;
}
.float {
  float: left;
  width: 50px;
  height: 50px;
  margin: 4px;
  background-color: skyblue;
}
</style>

<div id="scrollContainer">
<div class="clamp">Line 1
Line 2
Line 3
Line 4…<div class="float"></div></div>

<script>
  window.addEventListener("load", () => {
    const scrollContainer = document.getElementById("scrollContainer");
    scrollContainer.scrollTop = scrollContainer.scrollHeight;
  });
</script>
